De-Deus Gustavo, Belladonna Felipe Gonçalves, Marins Juliana Roter, Silva Emmanuel João Nogueira Leal, Neves Aline de Almeida, Souza Erick Miranda, Machado Alessandra de Castro, Lopes Ricardo Tadeu, Versiani Marco Aurélio
Department of Endodontics, UFF - Universidade Federal Fluminense, Niterói, RJ, Brazil.
Department of Endodontics, UNIGRANRIO Universidade Grande Rio, Duque de Caxias, RJ, Brazil.
Braz Dent J. 2016 Oct-Dec;27(6):664-669. doi: 10.1590/0103-6440201601002.
This study aimed to evaluate the cause-effect relationship between canal preparation with ProTaper Universal (PTU) system and dentinal defects formation using micro-computed tomography (micro-CT) analysis. Forty mesial canals of mandibular molars with a type II Vertucci's canal configuration were scanned at an isotropic resolution of 14.16 µm. The sample was assigned to an experimental (n = 30) and a control (n = 10) groups, and the mesial canals were prepared with PTU system up to F2 instrument. The specimens from the experimental group were scanned and the cross-section images of the mesial roots, before and after preparation, were screened to identify the presence of dentinal defects. In the control group, the specimens were sectioned perpendicularly to the long axis of the root into 1-mm-thick slices (n = 80) and examined under optical microscope. Once a dentinal defect was detected, the slice was scanned through micro-CT. In the experimental group, dentinal micro-cracks were observed in 4,828 slices (24.04%). In all cross-section images, dentinal defects identified in the postoperative images were already present in the corresponding preoperative image. In the control group, 13 out of 80 slices (16.25%) had at least one dentinal defect visualized under stereomicroscopy, which was identified after a further micro-CT scanning. Micro-CT showed reliability as similar as optical microscopy in detecting dentinal defects, adding the possibility of tracking the dentinal tissue, before and after canal preparation, and providing a clear visualization of micro-cracks. Root canal preparation with PTU system did not induce the formation of new dentinal defects.
本研究旨在通过显微计算机断层扫描（micro-CT）分析评估使用ProTaper Universal（PTU）系统进行根管预备与牙本质缺陷形成之间的因果关系。对40颗具有II型Vertucci根管形态的下颌磨牙近中根管进行扫描，各向同性分辨率为14.16µm。样本分为实验组（n = 30）和对照组（n = 10），使用PTU系统对近中根管预备至F2器械。对实验组的标本进行扫描，筛选出预备前后近中根的横断面图像，以确定牙本质缺陷的存在。对照组中，将标本垂直于牙根长轴切成1mm厚的切片（n = 80），并在光学显微镜下检查。一旦检测到牙本质缺陷，就对该切片进行micro-CT扫描。在实验组中，在4828个切片中观察到牙本质微裂纹（24.04%）。在所有横断面图像中，术后图像中识别出的牙本质缺陷在相应的术前图像中已经存在。在对照组中，80个切片中有13个（16.25%）在立体显微镜下至少有一个牙本质缺陷，在进一步的micro-CT扫描后得以确定。Micro-CT在检测牙本质缺陷方面显示出与光学显微镜相似的可靠性，增加了追踪根管预备前后牙本质组织的可能性，并能清晰显示微裂纹。使用PTU系统进行根管预备不会诱导新的牙本质缺陷形成。
